bomb recharge thread, more

[Mike Arman <armanmik@n-jcenter.com>]

Eric Maxon, our resident "Manicured Mechanic" says:
>
>   I missed most of this thread, but refilling, or in any way attempting
>to repair a dead "bomb" seems ludicrous to me.

Why? If there's an easy way to save a quick $250? Of course, it is a big
"if", but it's worth at least a look. After all, we fix our window
switches, and they cost less than $250 each (so far, anyway).

>
>warning... commercial message comming up...
>I sell them for $250, NEW.  (manufactured by Lemforder Metallwaren of W.
>Germany.)
>end commercial message.

Commercial message noted - no problem with that - if the recharge procedure
proves to be impossible/impractical/dangerous etc, I'll most likely buy one
from you - I'm exploring alternatives and solutions, not saying "don't ever
spend any money!".


>
>So your bomb is dead... Where do you think the gas went??  Unless you're
>talking about a 20 year old Citroen that's been rusting away in some
>junk yard for 20 years, the gas most likely leaked through the thin
>septum/inner sphere into the hydraulic system, not through the thick
>metal outer shell of the sphere.  Even if you have the equipment and
>wherewithall to cut the bomb open, weld it shut properly, weld a gas
>fitting onto it, and fill it with gas, where the hell are you going to
>get a new septum?

Techno-geek logic coming: If the diaphragm has a linear leak-down rate, a
recharge (again, if feasible) should last another seven years. If the
diaphragm leaks progressively faster with age, if it lasts five years,
that's still OK. If the leakage rate increases drastically at seven years
(or so), then this may not be practical. Obviously, if the diaphragm is
torn, the bomb is junk. Again, we're just in the looking around stage on this!


>
>When these babies fail, they usually still have plenty of gas pressure
>inside, but they don't work right because the check valves are clogged
>with dirt.  The valve body is "permanently" assembled-- another can of
>worms.
>I still have a couple of bombs here with stuck check valves, and will
>someday attempt to flush the valves with my Bosch K-Jetronic fuel
>injector tester/cleaner-- If this doesn't work, I'll throw them away.
>If you want to spend $400 on this machine, you can try it too-- or just
>get a new bomb for $250!  (oops.. more commercialism.)
>


This is (yet another) failure mode. If in fact bad bombs could be fixed
with a check valve cleanout, wouldn't that be worth $50 to $75? It would be
great if that was all that went wrong with them - like cleaning the
throttle plate, for instance. Why not take a shot with the injector
tester/cleaner, and see what happens?



>Provided the check valves work properly, here's your shopping list for
>repairing a depressurized bomb:
>
>Used MIG welding outfit, with filled nitrogen tank and lines:
>$1000-$1500
>Lots of practice using above:   6 months of spare time (pricele$$)
>Crash course in conversational German:  $250
>Round trip extreme bargain airfare to German city of your choice: $400
>Rental of appropriate car in Germany for 1 week: $1000 (hmmm...maybe an
>S4?)
>Food and lodging in Germany for 1 week:  $200 (sausages, beer, and the
>back seat of the S4)
>Wining and dining of Lemforder executive:  $500
>Replacement parts for your dead bomb:  Free (see above)

(Yeah, but if I made a business of it, all this would be tax deductable!!!!)


Well, lemesee, first thing is to determine where the bomb was filled from
in the first place. A cursory look at the one on my bench shows no external
fill points on the nitrogen side of the bomb - the mounting stud is held on
with three small spot welds, and covers the only logical place for a filler
hole. Once I change the bomb (was going to do it last weekend, but it
rained), I'll take the stud off the bad one and see if that's where the
filler is. Lemforder may surprise us all: Wouldn't it be great if we found
a football-style filler plug which we just stick an inflator needle into
and fill as required - yeah, Mike, dream on!

The points here are follows (summary of thread to date):

1. No danger of drilling dead bomb, assuming normal precautions taken.
Drilling is recommended disposal procedure anyway.

2. Handling of 2,000 psi nitrogen is not a problem.

3. Need to determine fill point, valve configuration and installation.

4. How long will the fix last? Have to try some and see. Best outcome would
be seven more years. Worst outcome would be not at all.

5. Other problems may exist in a particular bomb besides nitrogen
leak-down. Some will not be repairable.

>
>Good luck!
>
>Eric Maxon "The Manicured Mechanic"

Eric, your "Good luck!" is appreciated, even though I somehow don't think
that is how you intended it (grin). That's OK, though, I promise not to be
insulted or start a flame-fest. There is the distinct possibility that this
will turn out not to be possible, but at least we will have looked at it
before doing what the dealers want us to do - buy a new everything - fix
nothing - throw it all away without even trying. I do note that you have a
few bad bombs lying around - I doubt that you just have them around because
you're making a collection of them  . . . you must have something in mind,
or you'd just throw them out. (wink wink nudge nudge)

It is also possible that I'm doing this because I just like to fix things
(where possible). Heck, I've got an Audi, right? I've fixed all sorts of
strange stuff, from a Bulova Accutron wristwatch (the one with the tuning
fork) to doing a brake job on a DC-7 - 128 brake pads on multi-disc brakes
- to fixing VGA monitors, and I install my own multi-line phone systems,
KSU and all. It's just a HOBBY - my business is international finance
(commercial plug!).

With best regards,

Mike Arman